(a) Field of the Invention
The present invention relates to an apparatus and a method for learning a touch point of an engine clutch of a hybrid electric vehicle and more particularly, to an apparatus and a method for learning a touch point of an engine clutch of a hybrid electric vehicle that learns the touch point of the engine clutch based on a change of an engine torque during the hybrid electric vehicle running
(b) Description of the Related Art
Generally, a hybrid electric vehicle is driven by an engine which generates torque from fuel combustion and an electric motor which generates torque from an electric battery. Hybrid electric vehicles can be provided with optimum output torque, based on how the engine and the motor are operated while the vehicles are driven by the two power sources, that is, the engine and the motor.
In the hybrid electric vehicle, to transfer power of the engine to a driving shaft, an engine clutch is mounted between the engine and the motor. The hybrid vehicle provides an electric vehicle (EV) mode that provides running of the vehicle with a torque of the motor and a hybrid electric vehicle (HEV) mode that provides running of the vehicle with the sum of an engine torque and a motor torque based on whether the engine clutch is coupled. The hybrid electric vehicle estimates and learns a touch point of the engine clutch for a stable power delivery and a rapid torque response.
A transmission mounted electric device (TMED) type of the hybrid electric vehicle which includes an automatic transmission uses a wet engine clutch and learns the touch point of the engine clutch when a shift stage is a park (P) stage or a neutral (N) stage. However, the hybrid electric vehicle which includes a dual clutch transmission (DCT) uses a dry engine clutch, so frequent learning of the touch point of the engine clutch is necessary compared to the wet engine clutch. Moreover, a conventional method for learning the touch point of the engine clutch applied to wet engine clutch may be less accurate.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.